The Animal Resource Program at MIT represents a vital resource that is central to the various biomedical research missions of the Institute. This proposal seeks funds to renovate and equip the E25 animal facility in a manner consistent with current NIH and AAALAC standards. E25 is a critical component of the centralized MIT Animal Resource Program that encompasses 174,000 gsf of space housing 104,000 animals on a daily basis. The following specific aims are documented in this proposal. Specific Aim 1: To extensively renovate and expand an existing 25 year old animal facility, E25, comprising 16,430 gsf with 11,105 nsf of usable housing, procedural, surgical, and quarantine space to allow continuation of biomedical research involving multiple species of animals. Specific Aim 2: To equip E25 with a tunnel washer, bedding dispenser and vacuum disposal system, ventilated rodent housing and mouse transfer stations, to maximize space and personnel efficiency and protection of mice from acquiring infectious murine pathogens. The specific improvements are directly related to the long term goal of MIT's Animal Resource Program, which is to provide the best possible environment for scientific inquiry supported by NIH and other sources, concurrently maintain AAALAC accreditation, and ensure the highest standards of humane care and use of laboratory animals.